1. Field of the Invention
The present invention relates to an end face polishing apparatus for polishing an end face of a rod-shaped member such as a fiber for optical communication.
2. Description of the Background Art
Fibers for optical communication are adhesively secured in the central hole of a ferrule, a main member of a connector, and then the ferrule end face and the end face of fibers are polished together and thus finished into a smooth, mirror surface. If the polished end faces of the ferrule and the fibers are not vertical to the central axis of the ferrule or if there is a flaw on the polished faces, the precision in positioning such ferrules as they are connected facing each other in an optical connector is lowered, and the loss increases. Therefore, the face of the ferrule including the optical fibers must be polished with high precision.
A conventional apparatus for polishing the end faces of optical fibers is disclosed for example by Japanese Patent Laid-Open No. 26456/1991. The disclosed end face polishing apparatus includes an eccentric adapter that rotates on a circle concentric with a rotating disc, and a planetary gear that transmits the rotation of a revolving motor to the eccentric adapter. These elements are coupled in a lapping machine, so that the lapping machine is allowed to rotate and revolve, while the end faces of a plurality of ferrules held by a polishing fixture are pressed against a lapping member secured to the lapping machine for lapping.
As described above, in the conventional optical fiber end face polishing apparatus, the plurality of ferrules held by the polishing fixture are pressed by a spring or the like against the lapping member secured to the lapping machine that rotates and revolves. However, the ferrules are polished based on time, and the polishing length for the ferrules cannot be controlled. When the ferrules mounted on the polishing fixture have the same length, there would be no problems. However their lengths are not equal because of the precision of ferrules or adhesive used to secure optical fibers coming out from the tip ends of ferrules and cured. When therefore such ferrules having different lengths are slid into contact with the lapping machine, the polishing fixture could be inclined relative to the lapping machine, and the lapping angle, the radius of curvature and the eccentricity could be deviated. The ferrules after the polishing could have different lengths.